The present invention concerns a water bearing household appliance, for example a laundry washing machine or a dishwasher, and a method for operating this appliance.
Nowadays it is known using water bearing household appliances, for example laundry washing machines and dishwashers, in which one or more items (e.g. pieces of laundry or dishware) can be loaded and treated (e.g. washed) with water and one or more additives (e.g. washing/rinsing products).
The dosage or the additive is always a tricky issue, since a too low amount of additive could compromise the washing effectiveness, while a too high amount of additive has the problem that some additive can settle on the washed items and remain on the latter even after unloading them from the appliance, and/or can be a source of pollution.
The correct amount of additives is related to the specific treating cycle (e.g. washing cycle), and to the amount (or quantity, or weight) of loaded items.
There is therefore the need to know the exact amount of additive which has to be provided to the appliance in relation to the selected treating cycle and to the amount of loaded items.
As stated above, a water bearing household appliance could be, for example, a laundry washing machine or a dishwasher.
It is underlined that in the present application the expression “laundry washing machine” will refer to both simple laundry washing machines (i.e. laundry washing machines which can only wash and rinse laundry) and laundry washing-drying machines (i.e. laundry washing machines which can also dry laundry).
Known laundry washing machines generally comprise an external casing provided with a washing tub which contains a rotatable perforated drum where the laundry (in this case the items to be washed) is placed.
The drum is rotated by an electric motor which may be connected to a rotating shaft of the drum by a belt pulley system, or may be a so called “direct drive motor”, that is a motor fixed to the washing tub and directly connected to the rotating shaft of the drum.
A loading/unloading door ensures access to the tub and the drum.
Laundry washing machines typically comprise a detergent supply unit and a water inlet circuit for the introduction of water and additives, in this case washing/rinsing products (i.e. detergent, softener, etc.) into the tub. Known laundry washing machines are also provided with water draining devices to drain the water from the tub.
According to the known technique, a complete washing cycle typically includes different phases during which the laundry to be washed is subjected to adequate treatments. A washing cycle usually comprises a laundry wetting phase with addition of a washing products. i.e. detergent, and a main washing phase during which, according to the washing program selected by the user, the water contained in the tub is heated to a predetermined temperature and the drum is rotated, so as to apply a mechanical cleaning action to the laundry. After the main washing phase the water contained in the drum is drained from the tub. A successive step of the cycle comprises a rinsing phase which usually comprises one or more rinsing cycles. In each rinsing cycle, clean rinse water is added to the laundry, the drum is rotated, and the water is then drained from the tub to the outside of the washing machine. After the rinsing phase a final spinning phase allows the extraction of the residual water contained in the wet laundry. In the spinning phase the drum is rotated, typically at a high rotation speed to obtain the extraction of the water from the laundry. The water extracted during the spinning phase is drained towards the outside by means of the water draining devices.
Some known washing machines are also provided with a weight measuring device configured to measure the weight of the laundry which is loaded in the washing drum, and with a logic unit, which is configured to determine the necessary amount of washing product to be used on the basis of the measured weight, and to display by the user interface the amount of detergent to be load on the detergent supply unit.
For example, JP 6233894 discloses a washing machine which is provided with a control panel comprising key switch operating as input means for allowing user to manually input the type of washing product, namely the detergent to be used “concentrate” “standard” and “liquid”, and setting the water surface level. The washing machine is further provided with a microcomputer, which is configured to: detect the amount of loaded laundry, set the water surface level based on the detected amount of loaded laundry, and determine the amount of washing product to be used, on the basis of the selected washing product, the set water surface level and the amount of loaded laundry. The microcomputer is further configured to display the determined amount of washing product by a common display window arranged in the control panel.
However this known washing machine is not able to determine the correct amount of washing product to be used in the washing cycle when the kind of washing product selected by the user is not stored in the microcomputer. Moreover, detergent-producers often modify features of washing products i.e. amount of washing product to be used for kilo of laundry during determined washing programs. In this case, microcomputer of the washing machine (disclosed in JP 6233894) may determine amount of detergent based on incorrect data, and consequently displays incorrect information about amount of washing product to be used.
US 2010/0186460 A1 discloses a washing machine which operates using a method for adding solid or liquid detergent active ingredients in portions and comprises an electronic programme control unit in addition to devices for entering and/or determining information concerning the desired or required composition of a treatment programme, for determining and/or entering washing-related parameters, i.e. the type of washing introduced into the washing machine, the degree of soiling and/or the weight of said washing. Information concerning the detergent active ingredients and the washing is read in from automatically readable information carriers by means of a read device and the programme control unit calculates and issues recommendations for the addition of a particular type of a detergent active ingredient and the amount of said ingredient in conjunction with this information, the chosen treatment programme and the washing-related parameters. In detail, the washing machine comprises a read device which recognizes transponders, i.e. RFID, tags. Such a read device recognizes washing items provided with transponders, i.e. packaging of a detergent active ingredient containing information concerning the accompanying detergent active ingredient. Instead of a read device and in the case of a washing machine is connected to a data network by means of a data network interface, the data can also be read in at any other point in the data network or be output from there back to the control unit of the washing machine.
Unfortunately, using the read device and/or data network interface in the washing machine, as disclosed in US 2010/0186460, causes the complexity and cost of the machine to increase. In addition, washing machine having read device disclosed in US 2010/0186460 holds users to use detergent packaging provided with transponders.